Prepare the sweet potatoes: Start by preheating your oven to 400°F (200°C). Wash 3 1/2 cups of purple sweet potatoes thoroughly, then place them on a baking sheet. Bake for about 30-40 minutes or until they are tender when pierced with a fork. Once done, let them cool slightly, then scoop out the flesh.
Toast the sesame seeds: While the sweet potatoes are baking, take about 1/3 cup of sesame seeds and toast them in a dry skillet over medium heat. Stir occasionally until they are golden brown and fragrant. Set aside to cool.
Mix the wet ingredients: In a large mixing bowl, combine the mashed sweet potato flesh, 3 tablespoons of tahini, 1/2 cup of hemp milk, 1 tablespoon of lime juice, and 1 tablespoon of orange juice. Mix well until you achieve a smooth consistency.
Add the dry ingredients: Gradually add 4 tablespoons of arrowroot flour and 1/4 cup of almond flour to the wet mixture. Stir until a sticky dough forms. If the mixture feels too wet, you can add a bit more arrowroot flour.
Shape the cookies: Preheat your oven to 320°F (160°C) and line a cookie sheet with parchment paper. Using your hands, form small balls of dough (about 1-2 inches in diameter). Roll each ball in the toasted sesame seeds to coat evenly, then flatten them slightly to form cookies.
Bake the cookies: Place the sesame-coated cookies on the prepared baking sheet. Bake in the preheated oven for about 15 minutes or until they are lightly golden and firm to the touch. Once baked, remove them from the oven and allow them to cool on a wire rack before serving.